UK Inflation Impact Calculator (CPI / CPIH / RPI)

Plain JavaScript

Convert a UK amount between two years using Office for National Statistics (ONS) inflation indices. Runs locally in your browser — no logins, no ads, no tracking.

Inputs

Tip: If you’re not sure, use CPIH — it’s the ONS headline measure and includes housing costs.
Data & notes series, methodology, CPI/CPIH/RPI explained

Source series pages (ONS MM23 Consumer price inflation time series): CPI D7BT, CPIH L522, RPI CHAW.

This tool uses ratios within a series, so the index base year doesn’t affect the result. “Use latest available” sets the end year to the latest year present in the embedded dataset (annual average).

CPIH — Consumer Prices Index including Housing (ONS preferred)
  • Includes everyday goods and services, plus owner occupiers’ housing costs and council tax.
  • The ONS headline measure for UK inflation.
  • Best default for broad “cost of living / purchasing power” comparisons.
CPI — Consumer Prices Index
  • Includes everyday goods and services, but generally excludes most owner-occupier housing costs and council tax.
  • Often used for international comparisons.
  • Useful if you specifically want to exclude housing from the measure.
RPI — Retail Prices Index (legacy measure)
  • Older methodology; still used for some contracts (e.g. certain rail fares, index-linked agreements).
  • Typically runs higher than CPI/CPIH.
  • Most appropriate when something is explicitly linked to RPI.
Quick choice guide
  • Not sure? Use CPIH.
  • Use CPI for international comparisons or to exclude housing.
  • Use RPI only when a contract or dataset is explicitly RPI-linked.

Results

Equivalent amount in end year
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Purchasing power change (start → end)
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Average annual inflation (compound)
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Inverse view (what the end-year amount was “worth” in the start year)
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Permalink (copies current settings)
Disclaimer not financial advice
Educational use only; not personalised financial advice. Results are approximate and exclude taxes, wages, interest, asset prices, and personal spending patterns.